Recently, a secondary battery, which can be charged and discharged, has been widely used as an energy source for wireless mobile devices. Also, the secondary battery has attracted considerable attention as a power source for electric vehicles and hybrid electric vehicles, which have been developed to solve problems, such as air pollution, caused by existing gasoline and diesel vehicles using fossil fuel.
Small-sized mobile devices use one or several small-sized cells for each device. On the other hand, medium- or large-sized devices, such as vehicles, use a medium- or large-sized battery system having a plurality of cells electrically connected with each other because high output and large capacity is necessary for the medium- or large-sized devices. Generally, a battery module is manufactured by mechanically and electrically connecting a plurality of battery cartridges having unit cells, the mechanical characteristics of which are low, mounted therein, and a plurality of battery modules are connected with each other, whereby such a medium- or large-sized battery system is manufactured.
It is required that the medium- or large-sized battery system have a compact structure, if possible, depending upon the characteristics of a device to which the battery system is applied and that the battery system have excellent mechanical properties and stable electrical connection. It is possible that a great external force is applied to a particular device, such as an electric vehicle and a hybrid electric vehicle, during the operation of the device. As a result, a great external force is also applied to a battery system used in the device.
When a housing is used to improve mechanical and electrical connection such that the battery system can be mounted in the housing, however, the overall size and weight of the system are increased, which is not desirable.
Consequently, when a unit for electrically connecting components of the battery system can also be used as a unit for mechanically connecting the components of the battery system, the compact structure may be realized. Some conventional arts have proposed connecting members having various structures. However, most of the connecting members may be easily damaged when an external force is applied to the connecting members.